Author
Topic: Building a large bot to haul things. (Read 2470 times)

I am going to throw a question up here to get a few ideas on what people think might work, before diving in and buying a lot of things I might not need.

I am in a wheelchair and getting older and don't really have anyone around to help me, so I decided it was time to build a bot to be able to carry things from one place to another. This is mainly needed outside, and I have some gravel and slight inclines that it will have to go on.

I would like for the bot to be able to carry up to say 200 pounds.

Want to be able to slide things out of my van, (it doesn't have to be able to unload anything) just a flat place I can tie things down to, or maybe put some sides on.

I am pretty good with building things, have both a mig and a tig welder, tons of tools and such, so that part I don't think will be much of a problem.

I have been into R/C racing for many years, and would like to run it off a wheel style radio, rather then two sticks, and use Spektrum, or 2.4ghz to control it, since that is what I have gone to on all the radios. Keeps the antennas nice and short and can just hang the transmitter around my neck, and go and do my thing.

Well you could very well make a "haulchair" out of a power wheelchair. :-) You start with a frame/motor/battery/control that works, and alter the structure to be a place where you can put stuff. The welding part sounds like a piece of cake for you.

Converting the controls would depend on the wheelchair controls. Likely, though, that it would be not be a difficult task.

This sounds like a great project. Consider taking a lot of photos as you go.

As for controlling with the pistol grip TX, you could hook up a V-Tail mixer for RC airplanes. That way, when you pull on the throttle, the two motors will both go forwards (or backwards). But when you turn the steering wheel, they will go in opposite directions.

I convert the 2-channel R/C output from my receiver to a serial command to the Dimension Engineering Sabertooth 2X25 motor drive (and a dual PWM signal for an H-bridge if used). This is implemented on a PIC 16F876A microcontroller. I put quite a bit of thought and experimentation into accel/decel control and signal loss detection. Do you have any microcontroller experience? Let me know if you want the C code.

Yes, I think the welding and building the frame would be the least of my problems on things.

I have been looking around at a lot of the BattleBot controllers and think they would do the electronics like I wanted. I could do it through a lot of relays and servos, but hate going that route, would like to keep it clean and simple.

Well you could very well make a "haulchair" out of a power wheelchair. :-) You start with a frame/motor/battery/control that works, and alter the structure to be a place where you can put stuff. The welding part sounds like a piece of cake for you.

Converting the controls would depend on the wheelchair controls. Likely, though, that it would be not be a difficult task.

This sounds like a great project. Consider taking a lot of photos as you go.

Good Idea on the V-Tail mixer. A lot of my helicopter radios I have messed with in the past years are capable of doing that mix through the radio, and I am think that the one Futaba 3PK radio I have will do that also.

I am running dual motors on a Rock Crawler so I can run the front at a higher rpm then the back motor. I will mess around a bit with that to see what I find out.

As for controlling with the pistol grip TX, you could hook up a V-Tail mixer for RC airplanes. That way, when you pull on the throttle, the two motors will both go forwards (or backwards). But when you turn the steering wheel, they will go in opposite directions.

I have messed around some with micfocontrollers, but it has been many years, as it seemed everything was getting larger I wanted to use them on, and they were drawing way too much current, then the newer radios are building a lot of that into them now.

As I stated in the last message, I am going to see if I can combine the steering into the mix when I steer, much as boats change the rudders.

I convert the 2-channel R/C output from my receiver to a serial command to the Dimension Engineering Sabertooth 2X25 motor drive (and a dual PWM signal for an H-bridge if used). This is implemented on a PIC 16F876A microcontroller. I put quite a bit of thought and experimentation into accel/decel control and signal loss detection. Do you have any microcontroller experience? Let me know if you want the C code.

and onto the topic, do you want to buy or make your own boards? and the wheelchair idea seems excellent! i think you could quite easily hack the chair into a platform that you could hook up the motors and battery to.

i'm going to throw an idea i have had for a little while, Take a Monster wheels car for toddlers ( those mini powered cars that go on the side walks) cut out the frame so that it will be mostly used for just a basic bin, attach a radio controller into the circutry and you have something that can move heavy objects... to actually place the objects i'm suggestioning possibly an arm or scissor lift inside of it... i don't know how plausible that is ... but your best bet is too probably look at past competitions of the first robotics competition... i know that in 2005 or 2006 the object of the game was to pick up and lift large tetrahedrons to a height of 6, 9, and 12 feet... the last idea i have for you is basically a flatbed with a scissor lift under it and a mechanism to push things off the flat bed as for getting them back on you would need another mechanism good luck =)